In a linear guiding portion of a work table of a machine tool or any one of various conveying devices, there is widely used a rolling guiding device in which a movement block with a movable member such as a table mounted thereon moves continuously along a raceway rail. In a rolling guiding device of this type, the movement block is assembled to the raceway rail through the intermediation of a large number of balls, and the balls roll along while bearing a load between the movement block and the raceway rail, whereby it is possible for the movable member mounted on the movement block to make a smooth movement along the raceway rail while involving very little resistance. The movement block is equipped with an endless circulation path for the balls, and the balls are caused to circulate within this endless circulation path, whereby it is possible for the movement block to move continuously along the raceway rail.
The raceway rail has a ball rolling groove extending in the longitudinal direction, and the movement block has a load rolling groove opposed to the ball rolling groove of the raceway rail, so a load rolling path for the balls is formed by the ball rolling groove on the raceway rail side and the load rolling groove on the movement block side. That is, the balls are held in contact with the ball rolling groove on the raceway rail side and the load rolling groove on the movement block side, and roll along while bearing a load exerted therebetween. Further, the movement block has a non-load rolling path which is parallel to the load rolling path, and both ends of this non-load rolling path are communication-connected with the load rolling path by a pair of direction changing paths formed in an arcuate configuration. The balls are released from the load at an end of the load rolling path, and are detached from the ball rolling groove of the raceway rail to enter one of the direction changing paths, from which the balls roll toward the non-load rolling path. The balls having rolled through the non-load rolling path are returned to the ball rolling groove of the raceway rail by way of the direction changing path on the opposite side before rolling through the load rolling path again while bearing the load. In this way, the movement block is equipped with an endless circulation path for the balls in which the load rolling path, one direction changing path, the non-load rolling path, and the other direction changing path are successively connected; while circulating through this endless circulation path, the balls are alternately placed in a loaded state and an unloaded state, whereby the movement block can move continuously along the raceway rail without involving any limitations in terms of stroke.
The movement block is composed of a block main body formed of a steel allowing quenching, and a pair of end caps of a synthetic resin fixed to the front and rear end surfaces of the block main body; the load rolling groove is formed in the block main body by grinding, whereas the non-load rolling path is formed by forming in the block main body a through-hole of an inner diameter larger than the diameter of the balls and parallel to the load rolling groove, thus forming a tunnel-like non-load rolling path. The direction changing paths are formed in the end caps; by fixing the end caps respectively to the front and rear end surfaces of the block main body, the end portions of the load rolling path and the end portions of the non-load rolling path are connected by the direction changing paths, thereby forming an endless circulation path for the balls (JP 10-009264 A, Japanese Utility Model Publication No. 4-53459, etc.).    Patent Document 1: JP 10-009264 A    Patent Document 2: JP 4-53459 A    Patent Document 3: JP 2001-227540 A